If they shoot good, shoot em. I would take one apart, weigth the bullet, charge, measure the col, cl, try to determine the bullet mfgr, and note it all down. I still use powder over 25+ yrs old, but not with current manuals. Powder changes some what from batch to batch. I am sure my IMR 4831 is not a mirror image of todays powder. So save your notes and apply to your search to match this load.
Jim